Firing mechanism for automatic firearms.



R. FROMMER. name MECHANISM r03 AUTOMATIC FIREARMS.

. APPLICATION FILED MAR. 25 I914. 1,159,004.

Patented Nov. 2, 1915.

BUDOLF FROMMER, 0F BUDAPEST, AUSTRIA-HUNGARY.

-FIRING MECHANISM FOR AUTOMATIC FIREARMS.

Application filed March 25, 1914.

To all whom it may concern.

Be it known that I, RUDoLF FROMMER, manager, a subject of the King of Hungary, residing at 158 Soroksari iit, Budapest, IX, Austria-Hungary, have invented certain new and useful Improvements in Firing Mechanism for Automatic Firearms, of which .the following is a specification.

In the construction of modern firearms, especially of automatic firearms one must, while keeping in view the greatest possible lightness of the weapon, take care especially to diminish as far as possible the weight of the breech mechanism, because the weight of the barrel or stock, or in the case of weapons to be fixed upon supports or carriages, the weight of the casing, is in a sense predetermined. Moreover, in the use of the long cartridges now employed, and in view of the large dimensions of the breech parts, necessitated by the high ballistic requirements, the only possible course for keeping the breech weight small, is to diminish the length of the breech as much as possible. In order to be able to do this to the extreme limit, it is necessary to have recourse to hammer l0cks,.in which the firing pin projecting slightly out of the breech toward the rear is driven by means of the released hammer against the percussion cap, because these constructions alone permit of the arrangement of the relatively shortest breech pieces. The firingpins of such breech pieces must, as is -well known, be pressed back by rather strong springs so that any unintentional discharge of the cartridge by the effect of contact with the firing pin during the closing of the breech, is prevented. The spring which presses back the firing pin oifers however also a resistance against the stroke of the hammer, which drives the firing pin forward, so that in breeches provided with such firing pins, if extremely powerful hammer springs are not supplied, a premature explosion is very often experienced. These premature explosions can only be avoided by the use of correspondingly weak return springs; but the strength of these springs must nevertheless stand in proportion to the mass which is to be held back. Consequently, the conditions become the more favorable, the smaller the mass of the firing pin is made. On the other hand, however, a firing pin necessitates both on account of the strain upon it and also in order that it may be correspondingly efficient, a

Specification of Letters Patent.

Patented Nov. 2, 1915.

Serial No. 827,034.

certain size and will act the better, the greater its size is. Between the requirements regarding the spring which presses back the firing pin and the requirements as regards the size of the firing pin, there is consequently a contradicting problem which has not been solved in a thoroughly satisfactory manner.

The object of my invention is to provide an arrangement of the firing pin in which, while the ordinary size of the firing pin is maintained or even increased, the spring which pushes it back can be very weak, this construction thus offering great security against premature explosions. This object I attain by the use of a firing pin made in two parts one being a front point and the other a rear transmitter, both parts being held separated during the operation of the breech. Due to this arrangement, on the forward stroke of the breech bolt, only the smaller part of the firing pin, viz, the point, can act upon the retaining spring, while the mass of the much heavier transmitter remains ineffective. For the purpose of firing both parts of the firin pin are brought into cooperation so that the act as a whole and consequently transmit the blow to the cartridge exactly as if they were an integral firing pin. Obviously in this arrangement of the firing pin, a comparatively very weak hammer spring is sufficient a fact which increases durability at the same time reducing the necessary dimensions of all the parts of the breech and consequently reducing the weight of the weapon.

In the drawing, one construction of the firing pin mechanism is shown in vertical longitudinal section, Figure 1 showing the mechanism with closed but not bolted breech, while Fig. 2 shows the device with bolted breech.

The breech bolt head 1 is connected in the manner of the well known straight pull breeches by means of screw threads and bars with the chamber 2. In the breech bolt head 1 is located the firing pin 4 normally held back by means of the spring 3; the toand-fro motion of this pin is limited by the stop pin 5. In the chamber Qis placed the transmitter 6 which is pushed forward by means of a weak spring 7 and in its foremost position rests by means of a disk 8 against a shoulder 9 in.the chamber. In the position illustrated in Fig. 1, the breech bolt head 1' is shown in its foremost position,

the chamber 2 being in its rear position, in which position the transmitter 6 does not come in contact with the pin 4. Only when the chamber 2 is moved also into its foremost position (Fig. 2) and the breech is bolted, can the transmitter 6 come in contact with the pin 4, when the transmitter in opposition to its spring 7 is pushed back a little, so that the disk 8 leaves the shoulder 9. But even then the momentum of the transmitter is irrelevant, its speed of movement being counteracted partly by the friction between the chamber and the breech frame and partly by the friction between the breech frame and the barrel during the closing of the breech mechanism. Upon the closing movement of'the breech therefore the momentum of pin 4- only comes into action, and this can be counteracted by a comparatively weak spring. If then the breech bolt is thrust forward by means of a spring, the breech bolt, as soon as it reaches the barrel will first come to a stop, so that the momentum of the pin 4 alone comes into action, this, momentum being absorbed by the spring 3.- Hereupon the breech bolt head 1 screws into the barrel the chamber 2 following, and only at this time, 2'. 6. just prior to the fire-arm being ready for firing do the pin 4 and the transmitter 6 come into contact, so that they are driven forward as one part by the hammer 10.

Claims:

1. In automatic fire-arms the combination with the breech frame and the movable breech bolt comprising a hollow chamber having a shoulder therein, of a firing-pin made of two parts, the firing pin proper and a transmitter, a weak spring normally holding back said pin, and a disk on said transmitter adapted to bear against the shoulder in said hollow chamber thereby preventing the said transmitter from coming in contact with said pin, while the said hollow chamber is in its rear position.

2. In automatic fire-arms the combination with the breech frame and the movable breech bolt comprising a hollow chamber having a shoulder therein, of a firing pin made of two parts, the firing pin proper and a transmitter, a weak spring normally holding back said pin, and a disk on said -transmitter adapted to bear against the shoulder in said hollow chamber thereby preventing the said transmitter from coming in contact with said pin, while the said hollow chamber is m its rear position, and a spring holdingsaid disk in contact with the shoulder.

In testimony whereof I affix my signature in presence of two witnesses.

RUDOLF FROMMER. Witnesses: v

Ffi'LsYs Sonrtirr ALEXANDER FARAG. 

